Wiring Patient Care Areas

Wiring Patient Care Areas

Examining the extra steps contractors must take when designing and installing electrical equipment in patient care areas

Patient care areas come in many shapes, sizes, and purposes. In some spaces, only a quick exchange of words occurs, or a bandage is promptly applied. In others, it could take 20 medical/surgical/nursing staff members 20 hr using 20 pieces of electro-medical equipment to diagnose a problem. Although these spaces fall at completely different ends of the spectrum, they all have one thing in common — the examination or treatment of patients. For this reason, electrical wiring in (and wires/cables leading to) many patient care areas requires additional safety measures beyond what's typically installed in a commercial office building.

What are the additional features and/or requirements of the normal and essential electrical system related to patient care areas? This article will address this question as well as examine which health care facilities are required to abide by such requirements.

It all starts with a definition

Technical committees of standards organizations, particularly the National Fire Protection Association (NFPA), have developed criteria for designers, engineers, contractors, and inspectors to help eliminate or reduce the number of electrical incidents. These criteria were based on the hazards and risks patients and staff would be exposed to during the time a patient was being examined or treated in a patient care area.

To make sure all parties involved use the term “patient care area” in the same manner, an NFPA technical committee developed a definition for it — a definition that has remained essentially the same for more than 40 yr. As listed in NFPA 99-2005, “Standard for Health Care Facilities,” it reads as follows: “Any portion of a health care facility wherein patients are intended to be examined or treated.”

Shortly after defining this term, the technical committee found it necessary to create two subcategories because the condition of patients — and the amount and type of electro-medical equipment used in the area — could vary widely. This subdivision of terms reflects both the difference in electrical equipment used and the type of procedures taking place. Again, as listed in NFPA 99, the two subcategories and their definitions are:

General care area — Patient bedrooms, examining rooms, treatment rooms, clinics, and similar areas in which it is intended that the patient will come in contact with ordinary appliances, such as a nurse-call system, electric beds, examining lamps, telephones, and entertainment devices.”

Critical care area — Those special care units, intensive care units, coronary care units, angiography laboratories, cardiac catheterization laboratories, delivery rooms, operating rooms, post-anesthesia recovery rooms, emergency departments, and similar areas in which patients are intended to be subjected to invasive procedures and connected to line-operated, patient care-related electrical appliances.”

If it's intended that patients will, at some point, be subjected to invasive procedures and connected to line-operated, patient care-related electrical appliances (thus meeting the definition of critical care area), the area or room must be wired not only to meet requirements of a general care area, but also to some additional electrical requirements as listed for critical care areas. It's also important to note that these terms are facility independent. Therefore, the same committee specified where these subcategories would be applicable to a particular facility — be it a patient care area in a dental office, medical building, hospital, or ambulatory surgical center.

Additional requirements in patient care areas

NFPA 99-2005 lists the following performance requirements for the “normal” electrical distribution system feeding all patient care areas. However, readers are cautioned to:

  1. Review Chapters 12-18 in NFPA 99 to learn in which health care facilities these requirements are applicable;

  2. Take into consideration that requirements in NFPA 99 are minimum performance requirements, which means limits can be exceeded if (or as) necessary; and

  3. Review Art. 517 in the NEC to learn how wiring is to be installed to meet these performance requirements.

  • Branch circuits feeding each patient bed location are to come from one normal branch circuit distribution panel (

  • There is to be at least one branch circuit from the emergency branch circuit distribution panel feeding each patient bed location (

  • Grounding circuits are to be installed such that replacing a receptacle or any installed equipment does not interrupt grounding in the rest of the patient care area — or that the resistance in the grounding circuit is not raised above an acceptable level (

  • Grounding circuits are to be at least equivalent to an electrically continuous copper conductor (

  • All new construction is to use a separate grounding conductor (

  • Where metal receptacle boxes are used, the connection between the receptacle grounding terminal and metal box is to be equivalent to a copper wire at least 12 AWG in size (

  • The grounding systems of the normal and essential electrical systems are to be interconnected (

  • Ground-fault protection, where required, is to be coordinated such that the downstream device opens for downstream ground faults (

  • Ground-fault circuit interrupters (GFCIs), where required, are to be listed (

  • Two methods can be used for fixed systems of 30V (DC or AC rms) or less (

  • Power receptacles are to have at least one highly dependable grounding pole (

  • A minimum number of receptacles in a patient bed location is required (

  • No receptacles are required in bathrooms or toilet rooms (, nor in patient care areas where medical staff believe they present unreasonable risks to patients (

  • Special grounding is permitted, but with conditions attached (

  • In areas meeting the definition of “wet (procedure) location,” two methods of providing further protection against electric shock are considered acceptable:

    1. The installation of an isolated power system; or

    2. The installation of GFCIs. The decision on which method to use is dependent on whether power interruption could be tolerated on first fault, line-to-ground (

Critical care area concerns

Wiring in critical care areas has to meet the requirements noted above, plus some additional rules. Once again, the three caveats noted at the beginning of the previous section need to be reviewed (i.e., applicability, exceeding minimum requirements, and installation requirements).

  • If facility management want all receptacles in a patient bed location to have power restored when normal power is interrupted, the circuits are to be served by at least two critical branch transfer switches (

  • A higher number of minimum number of receptacles in a patient bed location are required (i.e., more than the minimum number required for patient bed locations in general patient care areas) [].

Anesthetizing locations

This type of patient care area typically meets the definition of critical care area. Due to the uniqueness of activities performed in these rooms, such as when inhalation anesthetics are administered, additional performance requirements must be met to reduce the possibility of injury to patients or staff, including the following:

  • Since all anesthetizing locations are patient care areas, all 15 items listed in the first section above are applicable.

  • If the anesthetizing location further meets the definition of a “critical care area,” then the wiring requirements listed under the second section above also apply.

  • Receptacles for 250V, 50A service are to be designed not to accept 60A attachment plugs; however, receptacles for 250V, 60A service are permitted to accept 50A or 60A attachment plugs (

  • Wiring is to be installed in metal raceways or as required by Art. 517 in NFPA 70 (;

  • At least one battery-powered emergency lighting unit is to be installed in each operating room, and wired to circuits serving general area lighting [].

  • Receptacles are to be identified as to whether they are powered from an isolated power system or from grounded power (

  • Approved permanently installed equipment can be supplied power from a grounded distribution system if installed according to wiring requirements listed in Annex E.6.6.3 (

  • There are restrictions on how many operating rooms can be served by an isolated power system (,, and

  • Switches controlling ungrounded circuits are to have a disconnecting pole for each conductor (

Essential electrical systems

Chapter 4 in NFPA 99 lists performance requirements for three types of essential electrical systems (EESs) in all health care facilities. As noted in previous sections of this article, readers are cautioned as to the need to review Chapters 12 through 18 to learn which type of EES is required for a health care facility.

For Type 1 EESs, the performance requirements for wiring to, and in, patient care areas (general and critical) are as follows:

  • Patient care areas are included in the list of areas that are to be connected to the “critical branch” of the emergency system. As such, wiring for patient care areas is to be kept entirely separate of all other wiring and equipment ( and to be mechanically protected per NFPA 70 (

  • Receptacles or their cover plates in patient care areas are to have a distinctive color or marking and their number on a branch circuit minimized (

  • Switches in lighting circuits are to meet the requirements of Art. 700 in NFPA 70.

  • Any secondary circuits of transformer-powered communication or signaling systems in patient care areas do not have to be enclosed in raceways unless required by Chapter 7 in NFPA 70.

For Type 2 EESs, there are no specific requirements listed for patient care areas because it was not anticipated that facilities, for which a Type 2 EES would be applicable, would have patients (e.g., limited care facilities and nursing homes). However, the NFPA technical committee responsible for the application of EESs approved a change for the 2005 edition of NFPA 99 that requires nursing homes that admit patients (as opposed to residents) on electrical life support equipment to install a Type 1 EES from the alternate power source to that portion of the facility where these patients are treated. This presents some interesting wiring requirements for existing nursing homes that admit such patients.

Health care facilities that are permitted to install a Type 3 EES (i.e., those that are not a hospital, nursing home, or limited care facility) face no additional wiring requirements related to the EES unless the following two conditions exist:

  1. Electrical life support equipment is used, or

  2. Critical patient care areas are present.

In these two situations, the EES wiring requirements listed above for a Type 1 EES must be met.

Are these additional measures for safety sufficient, more than sufficient, or not restrictive enough? No matter how you classify them, they are all based on more than 40 yr of Code-change proposals and comments from the public.

Klein is the president of Burton Klein Associates in Newton, Mass. He can be reached at [email protected].

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.